(**
 * Copyright (c) 2013-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *)

type t =
  | Assertion of string
  | UnexpectedToken of string
  | UnexpectedTokenWithSuggestion of string * string
  | UnexpectedNumber
  | UnexpectedString
  | UnexpectedIdentifier
  | UnexpectedReserved
  | UnexpectedReservedType
  | UnexpectedSuper
  | UnexpectedSuperCall
  | UnexpectedEOS
  | UnexpectedVariance
  | UnexpectedTypeAlias
  | UnexpectedOpaqueTypeAlias
  | UnexpectedTypeAnnotation
  | UnexpectedTypeDeclaration
  | UnexpectedTypeImport
  | UnexpectedTypeExport
  | UnexpectedTypeInterface
  | NewlineAfterThrow
  | InvalidRegExp
  | InvalidRegExpFlags of string
  | UnterminatedRegExp
  | InvalidLHSInAssignment
  | InvalidLHSInExponentiation
  | InvalidLHSInForIn
  | InvalidLHSInForOf
  | ExpectedPatternFoundExpression
  | MultipleDefaultsInSwitch
  | NoCatchOrFinally
  | UnknownLabel of string
  | Redeclaration of string * string
  | IllegalContinue
  | IllegalBreak
  | IllegalReturn
  | IllegalUnicodeEscape
  | StrictModeWith
  | StrictCatchVariable
  | StrictVarName
  | StrictParamName
  | StrictParamDupe
  | StrictFunctionName
  | StrictOctalLiteral
  | StrictDelete
  | StrictDuplicateProperty
  | AccessorDataProperty
  | AccessorGetSet
  | StrictLHSAssignment
  | StrictLHSPostfix
  | StrictLHSPrefix
  | StrictReservedWord
  | JSXAttributeValueEmptyExpression
  | InvalidJSXAttributeValue
  | ExpectedJSXClosingTag of string
  | NoUninitializedConst
  | NoUninitializedDestructuring
  | NewlineBeforeArrow
  | FunctionAsStatement of { in_strict_mode: bool }
  | AsyncFunctionAsStatement
  | GeneratorFunctionAsStatement
  | AdjacentJSXElements
  | ParameterAfterRestParameter
  | ElementAfterRestElement
  | PropertyAfterRestProperty
  | DeclareAsync
  | DeclareExportLet
  | DeclareExportConst
  | DeclareExportType
  | DeclareExportInterface
  | UnexpectedExportStarAs
  | DuplicateExport of string
  | ExportNamelessClass
  | ExportNamelessFunction
  | UnsupportedDecorator
  | MissingTypeParamDefault
  | WindowsFloatOfString
  | DuplicateDeclareModuleExports
  | AmbiguousDeclareModuleKind
  | GetterArity
  | SetterArity
  | InvalidNonTypeImportInDeclareModule
  | ImportTypeShorthandOnlyInPureImport
  | ImportSpecifierMissingComma
  | MalformedUnicode
  | DuplicateConstructor
  | DuplicatePrivateFields of string
  | InvalidFieldName of string * bool * bool
  | PrivateMethod
  | PrivateDelete
  | UnboundPrivate of string
  | PrivateNotInClass
  | SuperPrivate
  | YieldInFormalParameters
  | AwaitAsIdentifierReference
  | YieldAsIdentifierReference
  | AmbiguousLetBracket
  | LiteralShorthandProperty
  | ComputedShorthandProperty
  | MethodInDestructuring

exception Error of (Loc.t * t) list

let error loc e =
  raise (Error [loc, e])

module PP =
  struct
    let error = function
      | Assertion str -> "Unexpected parser state: "^str
      | UnexpectedToken token->  "Unexpected token "^token
      | UnexpectedTokenWithSuggestion (token, suggestion) ->
          Printf.sprintf "Unexpected token `%s`. Did you mean `%s`?"
            token
            suggestion
      | UnexpectedNumber ->  "Unexpected number"
      | UnexpectedString ->  "Unexpected string"
      | UnexpectedIdentifier ->  "Unexpected identifier"
      | UnexpectedReserved ->  "Unexpected reserved word"
      | UnexpectedReservedType -> "Unexpected reserved type"
      | UnexpectedSuper -> "Unexpected `super` outside of a class method"
      | UnexpectedSuperCall -> "`super()` is only valid in a class constructor"
      | UnexpectedEOS ->  "Unexpected end of input"
      | UnexpectedVariance -> "Unexpected variance sigil"
      | UnexpectedTypeAlias -> "Type aliases are not allowed in untyped mode"
      | UnexpectedOpaqueTypeAlias -> "Opaque type aliases are not allowed in untyped mode"
      | UnexpectedTypeAnnotation -> "Type annotations are not allowed in untyped mode"
      | UnexpectedTypeDeclaration -> "Type declarations are not allowed in untyped mode"
      | UnexpectedTypeImport -> "Type imports are not allowed in untyped mode"
      | UnexpectedTypeExport -> "Type exports are not allowed in untyped mode"
      | UnexpectedTypeInterface -> "Interfaces are not allowed in untyped mode"
      | NewlineAfterThrow ->  "Illegal newline after throw"
      | InvalidRegExp -> "Invalid regular expression"
      | InvalidRegExpFlags flags -> "Invalid flags supplied to RegExp constructor '"^flags^"'"
      | UnterminatedRegExp ->  "Invalid regular expression: missing /"
      | InvalidLHSInAssignment ->  "Invalid left-hand side in assignment"
      | InvalidLHSInExponentiation -> "Invalid left-hand side in exponentiation expression"
      | InvalidLHSInForIn ->  "Invalid left-hand side in for-in"
      | InvalidLHSInForOf ->  "Invalid left-hand side in for-of"
      | ExpectedPatternFoundExpression -> (
          "Expected an object pattern, array pattern, or an identifier but " ^
          "found an expression instead"
        )
      | MultipleDefaultsInSwitch -> "More than one default clause in switch statement"
      | NoCatchOrFinally ->  "Missing catch or finally after try"
      | UnknownLabel label -> "Undefined label '"^label^"'"
      | Redeclaration (what, name)-> what^" '"^name^"' has already been declared"
      | IllegalContinue -> "Illegal continue statement"
      | IllegalBreak -> "Illegal break statement"
      | IllegalReturn -> "Illegal return statement"
      | IllegalUnicodeEscape -> "Illegal Unicode escape"
      | StrictModeWith ->  "Strict mode code may not include a with statement"
      | StrictCatchVariable ->  "Catch variable may not be eval or arguments in strict mode"
      | StrictVarName ->  "Variable name may not be eval or arguments in strict mode"
      | StrictParamName ->  "Parameter name eval or arguments is not allowed in strict mode"
      | StrictParamDupe -> "Strict mode function may not have duplicate parameter names"
      | StrictFunctionName ->  "Function name may not be eval or arguments in strict mode"
      | StrictOctalLiteral ->  "Octal literals are not allowed in strict mode."
      | StrictDelete ->  "Delete of an unqualified identifier in strict mode."
      | StrictDuplicateProperty ->  "Duplicate data property in object literal not allowed in strict mode"
      | AccessorDataProperty ->  "Object literal may not have data and accessor property with the same name"
      | AccessorGetSet ->  "Object literal may not have multiple get/set accessors with the same name"
      | StrictLHSAssignment ->  "Assignment to eval or arguments is not allowed in strict mode"
      | StrictLHSPostfix ->  "Postfix increment/decrement may not have eval or arguments operand in strict mode"
      | StrictLHSPrefix ->  "Prefix increment/decrement may not have eval or arguments operand in strict mode"
      | StrictReservedWord ->  "Use of future reserved word in strict mode"
      | JSXAttributeValueEmptyExpression -> "JSX attributes must only be assigned a non-empty expression"
      | InvalidJSXAttributeValue -> "JSX value should be either an expression or a quoted JSX text"
      | ExpectedJSXClosingTag name -> "Expected corresponding JSX closing tag for "^name
      | NoUninitializedConst -> "Const must be initialized"
      | NoUninitializedDestructuring -> "Destructuring assignment must be initialized"
      | NewlineBeforeArrow ->  "Illegal newline before arrow"
      | FunctionAsStatement { in_strict_mode } ->
          if in_strict_mode then
            "In strict mode code, functions can only be declared at top level or "^
            "immediately within another function."
          else
            "In non-strict mode code, functions can only be declared at top level, "^
            "inside a block, or as the body of an if statement."
      | AsyncFunctionAsStatement -> "Async functions can only be declared at top level or "^
          "immediately within another function."
      | GeneratorFunctionAsStatement -> "Generators can only be declared at top level or "^
          "immediately within another function."
      | AdjacentJSXElements -> "Unexpected token <. Remember, adjacent JSX "^
          "elements must be wrapped in an enclosing parent tag"
      | ParameterAfterRestParameter ->
          "Rest parameter must be final parameter of an argument list"
      | ElementAfterRestElement ->
          "Rest element must be final element of an array pattern"
      | PropertyAfterRestProperty ->
          "Rest property must be final property of an object pattern"
      | DeclareAsync -> "async is an implementation detail and isn't necessary for your declare function statement. It is sufficient for your declare function to just have a Promise return type."
      | DeclareExportLet -> "`declare export let` is not supported. Use \
          `declare export var` instead."
      | DeclareExportConst -> "`declare export const` is not supported. Use \
          `declare export var` instead."
      | DeclareExportType -> "`declare export type` is not supported. Use \
          `export type` instead."
      | DeclareExportInterface -> "`declare export interface` is not supported. Use \
          `export interface` instead."
      | UnexpectedExportStarAs -> "`export * as` is an early-stage proposal \
          and is not enabled by default. To enable support in the parser, use \
          the `esproposal_export_star_as` option"
      | DuplicateExport export -> (Printf.sprintf "Duplicate export for `%s`" export)
      | ExportNamelessClass -> "When exporting a class as a named export, \
          you must specify a class name. Did you mean \
          `export default class ...`?"
      | ExportNamelessFunction -> "When exporting a function as a named export, \
          you must specify a function name. Did you mean \
          `export default function ...`?"
      | UnsupportedDecorator -> "Found a decorator in an unsupported position."
      | MissingTypeParamDefault -> "Type parameter declaration needs a default, \
          since a preceding type parameter declaration has a default."
      | WindowsFloatOfString -> "The Windows version of OCaml has a bug in how \
          it parses hexidecimal numbers. It is fixed in OCaml 4.03.0. Until we \
          can switch to 4.03.0, please avoid either hexidecimal notation or \
          Windows."
      | DuplicateDeclareModuleExports -> "Duplicate `declare module.exports` \
          statement!"
      | AmbiguousDeclareModuleKind -> "Found both `declare module.exports` and \
          `declare export` in the same module. Modules can only have 1 since \
          they are either an ES module xor they are a CommonJS module."
      | GetterArity -> "Getter should have zero parameters"
      | SetterArity -> "Setter should have exactly one parameter"
      | InvalidNonTypeImportInDeclareModule ->
          "Imports within a `declare module` body must always be " ^
          "`import type` or `import typeof`!"
      | ImportTypeShorthandOnlyInPureImport ->
        "The `type` and `typeof` keywords on named imports can only be used on \
        regular `import` statements. It cannot be used with `import type` or \
        `import typeof` statements"
      | ImportSpecifierMissingComma ->
        "Missing comma between import specifiers"
      | MalformedUnicode ->
        "Malformed unicode"
      | DuplicateConstructor ->
        "Classes may only have one constructor"
      | DuplicatePrivateFields name ->
        "Private fields may only be declared once. `#" ^ name ^ "` is declared more than once."
      | InvalidFieldName (name, static, private_) ->
        let static_modifier = if static then "static " else "" in
        let name = if private_ then "#" ^ name else name in
        "Classes may not have " ^ static_modifier ^ "fields named `" ^ name ^ "`."
      | PrivateMethod ->
        "Classes may not have private methods."
      | PrivateDelete ->
        "Private fields may not be deleted."
      | UnboundPrivate name ->
        "Private fields must be declared before they can be referenced. `#" ^ name
        ^ "` has not been declared."
      | PrivateNotInClass -> "Private fields can only be referenced from within a class."
      | SuperPrivate -> "You may not access a private field through the `super` keyword."
      | YieldInFormalParameters -> "Yield expression not allowed in formal parameter"
      | AwaitAsIdentifierReference -> "`await` is an invalid identifier in async functions"
      | YieldAsIdentifierReference -> "`yield` is an invalid identifier in generators"
      | AmbiguousLetBracket -> "`let [` is ambiguous in this position because it is "^
          "either a `let` binding pattern, or a member expression."
      | LiteralShorthandProperty -> "Literals cannot be used as shorthand properties."
      | ComputedShorthandProperty -> "Computed properties must have a value."
      | MethodInDestructuring -> "Object pattern can't contain methods"
  end
